JP2024042635A - Mold structure, manufacturing method of in-core, in-core, and pipe fittings - Google Patents

Abstract

To provide a mold structure capable of keeping material costs and processing costs low and suppressing deformation of an in-core during molding, a manufacturing method of the in-core, the in-core, and a pipe fitting.SOLUTION: A mold structure 50 is used to mold an in-core 10 of a pipe fitting by injection molding. The mold structure 50 includes a mold 51 and a core pin 52. The mold 51 molds an outer peripheral portion 19 of the in-core 10. The core pin 52 molds an inner circumferential surface 15 of the in-core 10. The core pin 52 consists of a first core pin 57 and a second core pin 58 which are divided in an axial direction of the pipe fitting.SELECTED DRAWING: Figure 4

Description

The present invention relates to a mold structure, a method for manufacturing an in-core, an in-core, and a pipe joint.

Conventionally, inside buildings such as detached houses, condominiums, commercial facilities, and the like, internal water stop type and external water stop type pipe fittings are often used to connect pipes for water supply, hot water supply, or air conditioning equipment. With these types of pipe joints, pipes can be easily connected to the pipe joint by simply inserting the pipe into the pipe joint. In an external water stop type pipe joint, the in-core is brought into contact with the inner peripheral surface of the pipe, and the packing is sandwiched between the outside of the pipe and the inner peripheral surface of the joint.

In relation to in-cores, for example, according to the in-core manufacturing method shown in Patent Document 1, a cylindrical part is formed by press-drawing a plate material of a metal material such as stainless steel, and a flange part ( In other words, those that form a wing portion are known.
Further, for example, according to the in-core manufacturing method shown in Patent Document 2, after filling the cavity of a molding die with molten resin and molding the in-core, the mold is opened and a core pin is extracted from the inner peripheral surface of the in-core. A manufacturing method is disclosed.

JP2008-267549A Japanese Patent Application Publication No. 2016-223469

However, the in-core disclosed in Patent Document 1 has a problem in that material costs and processing costs are high because a metal material such as stainless steel is press-drawn. It is also possible to form the in-core by machining it from brass, etc., but since brass contains a small amount of lead, lead may be leached into the water or hot water after long-term use. .

Moreover, the in-core of Patent Document 2 needs to be supported in contact with the inner circumferential surface of the pipe, and is formed relatively long. Therefore, the core pin that is extracted from the inner circumferential surface of the inner core when the mold is opened is long. Therefore, when the core pin is extracted from the inner peripheral surface of the in-core, the in-core may be deformed.

The present invention has been made in view of the above-mentioned circumstances, and has a mold structure and an in-core manufacturing method that can reduce material and processing costs and suppress deformation of the in-core during molding. The present invention aims to provide a method, an in-core, and a pipe fitting.

In order to solve the above problems, the present invention proposes the following means.
<1> A mold structure according to one aspect of the present invention is a mold structure used for molding an inner core of a joint by injection molding, the mold structure comprising: a mold for molding a cylindrical outer peripheral portion of the inner core; and a core pin that forms a peripheral surface. The core pin is composed of a first core pin and a second core pin that are divided in the axial direction of the joint.

The in-core is formed by injection molding of a synthetic resin material using a mold structure. Thereby, the material and processing costs can be kept low compared to the case where the in-core is formed by pressing and drawing a metal material such as stainless steel.
Further, by dividing the core pin into the first core pin and the second core pin, the axial lengths of the first core pin and the second core pin can be kept short. Thereby, deformation of the in-core can be suppressed when the first core pin and the second core pin are extracted from the inner circumferential surface of the in-core.

<2> In the mold structure according to <1> above, the parting surface between the first core pin and the second core pin may be inclined so that the pin diameter increases in the drawing direction.

By inclining the dividing plane between the first core pin and the second core pin, a draft angle can be formed in the dividing plane between the first core pin and the second core pin. Thereby, when the first core pin and the second core pin are extracted from the inner circumferential surface of the in-core, deformation of the in-core can be better suppressed.

Here, if the core pin is integrally formed without being divided, the core pin becomes relatively long. Therefore, if a draft angle is formed on the dividing surface of the integral core pin, the pin diameter at the distal end of the core pin becomes too small and the pin diameter at the proximal end becomes too large. That is, in the in-core, it is conceivable that the thick portion corresponding to the tip of the core pin becomes too thick and the thin portion corresponding to the proximal end of the core pin becomes too thin.
Therefore, in the thick portion, the inner diameter of the inner circumferential surface becomes smaller, and the flow path diameter of the inner circumferential surface becomes smaller. As the flow path diameter of the inner circumferential surface becomes smaller, there is a concern that pressure loss due to a decrease in flow rate will occur when a large number of pipe joints are used, such as when repairing piping in an apartment building. Furthermore, it is possible that the moldability of the thin-walled portion deteriorates, resulting in short shots, and it is difficult to maintain the shape of the thin-walled portion.

Therefore, in this configuration, the core pin is divided into a first core pin and a second core pin, so that the axial lengths of the first core pin and the second core pin are kept short. Therefore, the pin diameter difference between the distal end and the proximal end of the first core pin can be kept relatively small. That is, it is possible to ensure a large pin diameter at the distal end of the first core pin and to keep the pin diameter at the proximal end small. Similarly, in the second core pin, the pin diameter difference between the distal end and the proximal end can be kept relatively small. That is, it is possible to ensure a large pin diameter at the distal end of the second core pin, and to keep the pin diameter at the second base end small.
Therefore, in the in-core, it is possible to ensure a large inner diameter of the thick portion corresponding to the portion where the tips of the first core pin and the second core pin are butted against each other. The inner diameter of the thick portion is the smallest diameter on the inner circumferential surface of the in-core. This makes it possible to ensure a large in-core flow path diameter.

In addition, in the in-core, the inner diameter of the thin portion corresponding to the base end of the first core pin can be kept small. This thin portion corresponds to one end of the in-core. One end of the in-core is a portion of the inner peripheral surface formed by the first core pin that has a maximum inner diameter. Further, in the in-core, the inner diameter of the thin wall portion corresponding to the base end portion of the second core pin can be kept small. This thin portion corresponds to the other end of the in-core. The other end of the in-core is a portion of the inner peripheral surface formed by the second core pin that has the largest inner diameter.
Therefore, by keeping the inner diameters of the one end and the other end of the in-core small, it is possible to ensure that the wall thickness of the one end and the other end of the in-core is suitable. Thereby, the moldability of one end and the other end of the inner core can be improved, and the moldability of the inner core can be ensured.

<3> In the mold structure according to <2> above, the taper angle of the dividing plane between the first core pin and the second core pin may be greater than 0° and less than or equal to 3°.

Here, when the taper angle of the split surface is 0°, when extracting the first core pin and the second core pin from the inner circumferential surface of the in-core, the inner circumferential surface of the in-core is formed to be smooth by the split surface. is difficult. For this reason, it is conceivable that the inner circumferential surface becomes defective in molding.
Moreover, when the taper angle of the dividing surface is made larger than 3 degrees, the inner circumferential surface of the in-core can be formed smoothly by the dividing surface. However, the opening diameter (that is, the flow path diameter) becomes too small at an intermediate position on the inner circumferential surface. Furthermore, in the in-core, the opening diameter (flow path diameter) at one end and the other end may become too large, and the wall thickness at the one end and the other end may become too thin. For this reason, it is difficult to ensure moldability at one end and the other end.

Therefore, the taper angle of the dividing plane was set to a range of greater than 0° and less than 3°. By ensuring the taper angle of the dividing surface is greater than 0°, the draft angle of the first core pin and the second core pin can be suitably ensured. Therefore, when extracting the first core pin and the second core pin from the inner circumferential surface of the in-core, the inner circumferential surface of the in-core can be formed smoothly by the dividing surface. Thereby, deformation of the in-core can be effectively suppressed.
Moreover, by suppressing the taper angle of the dividing surface to 3° or less, a large opening diameter (flow path diameter) at the intermediate position in the in-core can be ensured. Furthermore, by suppressing the taper angle to 3° or less, it is possible to suitably ensure wall thickness at one end and the other end in the in-core. Thereby, the moldability of the one end and the other end can be improved, and the moldability of the in-core can be ensured.
Accordingly, it is desirable to set the taper angle of the dividing surface to a range of greater than 0° and less than 3°. Furthermore, it is particularly desirable to set the taper angle of the dividing surface to a range of 0.5° or more and 3° or less.

<4> In the mold structure according to <2> above, the length of the first core pin and the second core pin may be 0.1 to 0.9 times the total length of the inner core.

Here, for example, if the pin length of the first core pin is 0 times or more and less than 0.1 times the total length of the in-core, the pin length of the second core pin is 0 times the total length of the in-core. .9 times larger. A draft angle is formed on the first dividing surface of the first core pin. A draft angle is formed on the second dividing surface of the second core pin. For this reason, if the pin length of the second core pin is greater than 0.9 times the total length of the in-core, the pin diameter at the tip of the second core pin will become too small, and the flow path diameter should be adjusted to a suitable size. difficult to secure.
Note that even if the pin length of the second core pin is set to be 0 times or more and less than 0.1 times the total length of the in-core, the first tip pin diameter of the first core pin becomes too small and the flow It is difficult to ensure a suitable path diameter.

Furthermore, for example, if the pin length of the first core pin is set to be greater than 0.9 times and less than 1 times the total length of the in-core, the pin diameter at the tip of the first core pin becomes too small and the flow It is difficult to ensure a suitable path diameter.
Note that even when the pin length of the second core pin is set to be greater than 0.9 times and less than 1 times the total length of the in-core, the first tip pin diameter of the second core pin 58 becomes too small. It is difficult to ensure a suitable flow path diameter.

Therefore, the pin length of the first core pin and the pin length of the second core pin were set to 0.1 to 0.9 times the total length of the in-core. Therefore, the pin length of the first core pin and the pin length of the second core pin can be kept relatively short. This makes it possible to realize the maximum flow path diameter. That is, it is possible to ensure a large flow path diameter at the intermediate position in the in-core.
Accordingly, it is desirable to set the pin length of the first core pin and the pin length of the second core pin to 0.1 to 0.9 times the total length of the in-core. Furthermore, it is particularly desirable to set the pin length of the first core pin and the pin length of the second core pin to a range of 0.3 to 0.7 times the total length of the in-core.

<5> A method for manufacturing an in-core according to one aspect of the present invention is a method for manufacturing an in-core using the mold structure according to any one of <1> to <4>, wherein the first core pin is The second core pin is first pulled out, and then the second core pin is pulled out in the opposite direction.

By pulling out the first core pin first and then pulling out the second core pin in the opposite direction, the in-core can be supported by the second core pin when the first core pin is pulled out. Thereby, the first core pin can be extracted from the inner circumferential surface of the in-core while the in-core is stabilized. Therefore, deformation of the in-core can be better suppressed.
Note that even if the second core pin is first pulled out from the second inner circumferential surface, and then the first core pin is pulled out from the first inner circumferential surface in the opposite direction, it is further possible to prevent the inner core from deforming in the same way. It can be suppressed well.

<6> In the in-core according to one aspect of the present invention, the inner circumferential surface is formed to have a minimum diameter at an intermediate position between one end and the other end.

The inner circumferential surface of the in-core is formed to have the smallest diameter at an intermediate position between one end and the other end. Therefore, for example, the first core pin having a draft angle can form the inner circumferential surface from one end to the intermediate position, and the second core pin having a draft angle can form the inner circumferential surface from the other end to the intermediate position. . Thereby, the pin lengths of the first core pin and the second core pin in the axial direction can be kept short. Therefore, deformation of the in-core can be suppressed when the first core pin and the second core pin are extracted from the inner circumferential surface of the in-core.

Here, the minimum diameter of the inner circumferential surface is determined by, for example, the pin length and draft angle of the core pin. That is, when the draft angles of the core pins are the same, by shortening the pin length of the core pins, a larger minimum diameter can be ensured. Therefore, by forming the inner circumferential surface of the in-core with the first core pin and the second core pin, a large minimum diameter at the intermediate position can be ensured. This makes it possible to ensure a large in-core flow path diameter.
In other words, in order to realize the maximum in-core flow path diameter, the core pin of the mold structure was divided into two. Thereby, the minimum diameter of the in-core was formed between the first core pin and the second core pin.

Furthermore, when the draft angles of the core pins are the same, the maximum diameter of the core pin (specifically, the base end portion) can be kept small by shortening the pin length of the core pin. That is, by forming the inner circumferential surface of the in-core with the first core pin and the second core pin, the maximum diameter can be kept small at one end and the other end of the in-core. One end and the other end are thin parts. Therefore, it is possible to ensure a suitable thickness at one end and the other end. Thereby, the moldability of the one end and the other end can be improved, and the moldability of the in-core can be ensured.

<7> In the in-core according to <6> above, the minimum diameter may be located at a position closer to the one end portion having a protrusion on the outer circumferential surface than the middle of the in-core in the axial direction.

Since the minimum diameter is located in the axial direction between the middle of the inner core and the one end side having a protrusion on the outer circumferential surface, the resin easily flows from the thick wall to the thin wall during molding.

<8> The in-core according to <6> above has a plurality of gate marks on the inner circumferential surface, and in the axial direction, from the middle of the in-core to the one end side having the protrusion on the outer circumferential surface. There may be.

When a plurality of gate marks are present on the inner peripheral surface of the in-core, a submarine gate (tunnel gate) is suitable. In the case of submarine gates, there is little gate residue after molding, and the gate diameter is small, making it easy to remove the runner. Since the plurality of gate marks are located from the middle of the in-core to one end, the formability of the end of the in-core can be improved even when the holding pressure is not high.

<9> In the in-core according to <6> above, a plurality of gate marks may be located on the end surface of the one end portion having a protrusion on the outer peripheral surface.

If a plurality of gate marks are present on the end face of one end, a pin gate is preferred. In the case of pin gates, the gate marks after molding can be made smaller, making the remaining gate less noticeable. Furthermore, in order to mold the end of the in-core as designed, it is necessary to apply a certain amount of holding pressure, but by employing a pin gate, it becomes easier to apply holding pressure.

<10> A pipe joint according to one aspect of the present invention includes a joint body and an in-core disposed on an inner circumferential surface of the joint body, and the inner circumferential surface of the in-core is formed between one end and the other end. It is formed to have the smallest diameter at the intermediate position.

Since the pipe joint includes an in-core whose inner circumferential surface is formed to have the smallest diameter at an intermediate position between one end and the other end, for example, a first core pin having a draft angle can be used to extend the inner circumference from one end to an intermediate position. The inner circumferential surface from the other end to the intermediate position can be formed by the second core pin having a draft angle. Thereby, the maximum diameter can be kept small at one end and the other end of the in-core. Therefore, the wall thickness of one end and the other end of the in-core can be ensured to be a suitable thickness. Therefore, the pipe joint including the in-core can ensure moldability at one end and the other end.

<11> In the pipe joint according to <10> above, the minimum diameter may be located at a position closer to the one end portion having a protrusion on the outer circumferential surface than the middle of the inner core in the axial direction.

Since the minimum diameter is located in the axial direction between the middle of the inner core and the one end side having a protrusion on the outer circumferential surface, the resin easily flows from the thick wall to the thin wall during molding.

According to the present invention, material costs and processing costs can be kept low, and deformation of the in-core during molding can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the pipe joint provided with the in-core based on 1st Embodiment of this invention, Comprising: It is a perspective view including a partial cross section. BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows the component structure of the pipe joint provided with the in-core based on 1st Embodiment of this invention. FIG. 1 is a sectional view showing an in-core according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing a mold clamping state of the mold structure according to the first embodiment of the present invention.

[First embodiment]
EMBODIMENT OF THE INVENTION Hereinafter, with reference to FIGS. 1-6, the metal mold|die structure, the manufacturing method of an in-core, an in-core, and a pipe joint which concern on one Embodiment of this invention are demonstrated.
As shown in FIGS. 1 and 2, the in-core 10 according to the first embodiment is included in a pipe joint (coupling) 100. The pipe joint 100 is a member for connecting a plurality of pipes (pipes) for water absorption, hot water supply, or air conditioning equipment in a building. The pipe fitting 100 and the pipe P connected to this pipe fitting 100 constitute a piping structure.

The pipe joint 100 comprises a cylindrical joint body 101 , an in-core 10 arranged on the inner peripheral surface of the joint body 101 , and a cap 102 provided on an end of the joint body 101 .
In the following description, the direction along the central axis of the joint body 101 (i.e., the pipe joint 100) is referred to as the axial direction, and the direction intersecting the central axis in a plan view of the joint body 101 from the axial direction is referred to as the radial direction. Also, the direction going around the central axis in the plan view is referred to as the circumferential direction.

A step 113 is formed on the inner circumferential surface of the joint body 101 at its axial end. The step 113 protrudes radially inward from the inner peripheral surface of the joint body 101. The step 113 is provided over the entire circumference in the circumferential direction. At the step 113, the inner diameter of the joint body 101 decreases in steps (stepwise) from the outside in the axial direction toward the inside. An in-core 10 formed separately from the joint body 101 abuts against the step 113 .
Hereinafter, the portion of the joint body 101 from the end surface of the joint body 101 to the step 113 will be referred to as the open end of the joint body 101.

An outer flange portion 101b and a male thread portion 101c are formed on the outer circumferential surface of each of the axially opposite ends of the joint body 101.
The outer flange portion 101b projects radially outward from the joint body 101. The outer flange portion 101b extends all the way around the outer peripheral surface of the joint body 101.
The male threaded portion 101c is formed in a portion of the outer circumferential surface of the joint body 101 that is located axially outside (that is, closer to the end of the joint body 101) than the outer flange portion 101b.

The cap 102 has a cylindrical shape with an outer diameter that gradually decreases in the axial direction. The cap 102 includes a first cylinder 102a having a female thread formed on its inner peripheral surface, and a second cylinder 102b located outside the first cylinder 102a in the axial direction.
The first cylinder 102a is screwed onto the male threaded portion 101c. A step 102d is provided on the inner circumference of the cap 102 at a portion corresponding to the boundary between the first cylinder 102a and the second cylinder 102b. The step 102d extends over the entire circumference in the circumferential direction. The step 102d contacts or approaches the end face of the joint body 101 facing outward in the axial direction.

The second cylinder 102b has a smaller diameter than the first cylinder 102a. The second cylinder 102b extends outward in the axial direction from the first cylinder 102a.
In the pipe joint 100, an accommodating recess 106 is formed between the joint body 101 and the cap 102 for accommodating the water stop part 103 and the fixing part 104. The accommodation recess 106 is formed between the step 102d and the end surface of the joint body 101 facing outward in the axial direction. The accommodation recess 106 extends over the entire circumference in the circumferential direction.

The joint body 101 is formed, for example, by injection molding of a synthetic resin material, cutting, casting, or forging of a metal material.
The cap 102 is formed, for example, by injection molding of a synthetic resin material, cutting, casting, or forging of a metal material.
Examples of the synthetic resin materials include crosslinked polyethylene, polybutene, vinyl chloride (PVC), polysulfone resin (PSU), polycarbonate resin (PC), polyamide resin (PA), polyacetal resin (POM), and polyphenylsulfone resin (PPSU). ), polyphenylene sulfide resin (PPS), glass fiber reinforced PPS, polyvinylidene fluoride (PVDF), etc., can be arbitrarily selected based on quality design according to the purpose. Further, other processing methods such as cutting or fusion may also be used.
The metal material may be arbitrarily selected from stainless steel, low-alloy steel, carbon steel, carbon steel for low-temperature use, alloy steel for low-temperature use, brass, gunmetal, aluminum alloy, magnesium alloy, etc. based on the quality design according to the application. be able to.

At each axial end of the pipe fitting 100, a packing 103a (sealing member), a base 103b, a retaining ring 104a (first retaining ring), a spacer 104c, and a retaining ring 104b (second retaining ring) are provided in this order toward the end of the fitting body 101. That is, the fixing portion 104 is located closer to the end than the water stop portion 103.
The packing 103a and the base 103b constitute a watertight portion 103. The watertight portion 103 prevents the contents of the pipe P from leaking out from the pipe joint 100.
The retaining ring 104a, the spacer 104c and the retaining ring 104b constitute the fixing portion 104. The pipe P inserted into the pipe joint 100 is fixed to the pipe joint 100 by the fixing portion 104.

The packing 103a (sealing member) is arranged on the inner peripheral surface of the joint body 101. Although there is one packing 103a in the illustrated example, a plurality of packings 103a may be provided at intervals in the axial direction. The packing 103a has an annular shape with a circular cross section. The packing 103a extends all the way around in the circumferential direction. In the illustrated example, an O-ring is employed as the packing 103a. The materials of the packing 103a include ethylene propylene diene rubber (EPDM), fluoro rubber (FKM), vinyl methyl silicone rubber (VMQ), acrylonitrile butadiene rubber (NBR), styrene butadiene rubber (SBR), and chloroprene rubber (CR). ) etc. can be adopted.

The base 103b is arranged between the packing 103a and the retaining ring 104a. The base 103b prevents the packing 103a and the retaining ring 104a from coming into contact with each other. The base 103b is formed into an annular shape. The base 103b extends over the entire circumference in the circumferential direction. The base 103b is fitted into the open end of the joint body 101. The base 103b is in contact with the axially outwardly facing end of the first stage of the joint body 101. The base 103b is hooked onto the first stage of the joint body 101 from the outside in the axial direction. The inner diameter of the base 103b is larger than the inner diameter of the packing 103a. The base 103b is formed, for example, by injection molding of a synthetic resin material, cutting, casting, or forging of a metal material.
Examples of the synthetic resin materials include crosslinked polyethylene, polybutene, vinyl chloride (PVC), polysulfone resin (PSU), polycarbonate resin (PC), polyamide resin (PA), polyacetal resin (POM), and polyphenylsulfone resin (PPSU). ), polyphenylene sulfide resin (PPS), glass fiber-reinforced PPS, polyvinylidene fluoride (PVDF), etc., can be arbitrarily selected based on quality design according to the application. Further, other processing methods such as cutting or fusion may also be used.
The metal material may be arbitrarily selected from stainless steel, low-alloy steel, carbon steel, carbon steel for low-temperature use, alloy steel for low-temperature use, brass, gunmetal, aluminum alloy, magnesium alloy, etc. based on the quality design according to the application. be able to.

The retaining rings 104a, 104b and the spacer 104c are arranged outside in the axial direction with respect to the base 103b. The retaining rings 104a, 104b and the spacer 104c are arranged in the accommodation recess 106 of the joint body 101. The retaining rings 104a, 104b and the spacer 104c are movably arranged in the axial direction with some play in the housing recess 106. The retaining ring 104a, the spacer 104c, and the retaining ring 104b are arranged in this order from the outside to the inside in the axial direction. The spacer 104c is disposed in the accommodation recess 106 so as to be sandwiched in the axial direction between the retaining ring 104a and the retaining ring 104b.

A step is formed on the axially inner side of the base 103b, and a corresponding step is provided on the joint body 101. This stage fixes the base 103b so that it does not move toward the back of the joint body 101. As a result, the packing 103a is prevented from being pinched between the base 103b and the joint body 101 and being crushed in the axial direction.

The retaining rings 104a and 104b prevent the pipe P from coming off. The retaining rings 104a, 104b have an annular flat part 1104a and a locking ring part 1104b, and gradually move radially inward in the flat part 1104a and axially inward. An extending locking ring portion 1104b is formed. That is, the locking ring portion 1104b of the retaining ring 104a is bent in the direction of the water stop portion 103 with respect to the flat portion 1104a, and the locking ring portion of the retaining ring 104b is bent in the direction of the spacer 104c with respect to the flat portion. It is bent to. The dimensions including the shape and thickness of both retaining rings 104a and 104b are the same.
The angle formed by the flat portion 1104a and the locking ring portion 1104b is, for example, 130° to 140°. The inner circumferential edge of the locking ring portion 1104b is located radially inner than the inner circumferential surfaces of each of the cap 102 and the spacer 104c. The inner diameter of the locking ring portion 1104b is equivalent to the inner diameter of the packing 103a.

The inner diameter of the locking ring portion 1104b is smaller than the outer diameter of the pipe P. When the pipe P is inserted into the fitting body 101, the inner peripheral edge of the locking ring portion 1104b bites into the outer peripheral surface of the pipe P, so that the retaining rings 104a and 104b prevent the pipe P from moving in the axial direction from the pipe fitting 100. Prevent it from coming off. Note that the locking ring portion 1104b is preferably divided into a plurality of ring pieces (teeth portions) in the circumferential direction.
The retaining rings 104a and 104b are formed, for example, by press working of a metal material.
The metal material may be arbitrarily selected from stainless steel, low-alloy steel, carbon steel, carbon steel for low-temperature use, alloy steel for low-temperature use, brass, gunmetal, aluminum alloy, magnesium alloy, etc. based on the quality design according to the application. be able to.

The spacer 104c is formed into an annular shape with a rectangular cross section that is longer in the axial direction than its thickness. The spacer 104c extends over the entire circumference in the circumferential direction. The inner diameter of the spacer 104c is smaller than the inner diameter of the open end of the joint body 101. The inner diameter of the spacer 104c is larger than the inner diameter of the retaining rings 104a and 104b (the inner diameter of the locking ring portion). A retaining ring 104b is sandwiched between the spacer 104c and the cap 102. The spacer 104c is fixed to the accommodation recess 106 of the joint body 101. The retaining ring 104a and the retaining ring 104b are movable in the axial direction between the base 103b and the spacer 104c, and between the spacer 104c and the inside of the cap 102, respectively, in the accommodation recess 106 of the joint body 101. It is stored in.

The spacer 104c is formed, for example, by injection molding of a synthetic resin material. Examples of the synthetic resin materials include crosslinked polyethylene, polybutene, vinyl chloride (PVC), polysulfone resin (PSU), polycarbonate resin (PC), polyamide resin (PA), polyacetal resin (POM), and polyphenylsulfone resin (PPSU). ), polyphenylene sulfide resin (PPS), glass fiber-reinforced PPS, polyvinylidene fluoride (PVDF), etc., can be arbitrarily selected based on quality design according to the application.

The number of retaining rings is not limited to two, and may be three or more. Also in this case, the spacer is sandwiched between the two retaining rings.
Increasing the number of retaining rings is preferable from the viewpoint of preventing the pipe P from coming off as it increases the hooking area with the pipe P, but if the number of retaining rings is too large, stress will be concentrated and the pull-out strength will decrease. Since the length of the fixing part becomes long, the overall length of the joint also becomes long, and the compactness deteriorates, so it is particularly preferable to use two retaining rings.

The base 103b, the retaining ring 104a, the spacer 104c, and the retaining ring 104b are housed in this order in the accommodation recess 106 between the enlarged diameter portion on the inner surface of the joint body 101 and the reduced diameter portion on the inner surface of the cap 102. There is. The length of the accommodation recess 106 in the axial direction is such that there is enough space between the retaining ring 104b and the reduced diameter portion of the cap 102.

As shown in Figs. 1 and 3, the incore 10 is formed into a cylindrical shape. The incore 10 is housed in the joint body 101 in a detachable state. The incore 10 is formed into a cylindrical shape and is arranged coaxially with the joint body 101. The axial ends of the incore 10 are the incore first end (one end) 10a and the incore second end (the other end) 10b. When the incore 10 is housed in the joint body 101, the incore first end 10a is located outside the axial direction of the incore second end 10b. The incore first end 10a is located inside the cap 102 (second cylinder). The incore second end 10b is located inside the joint body 101. The incore second end 10b is located inside the packing 103a in the axial direction. The incore 10 is located inside the packing 103a, the base 103b, the retaining ring 104a, the spacer 104c, and the retaining ring 104b.

The in-core 10 is a component that is inserted into the end of the pipe P to suppress the end from deforming inward in the radial direction. The in-core 10 consists of an in-core cylindrical part 12 that enters into the end of the pipe P, and an in-core proximal end part 13 that does not enter into the end of the pipe P but is exposed. Wing portions (protrusions) 14 are formed on the outer circumferential surface of the in-core base end portion 13 . In the in-core 10, the wing portion 14 is arranged closer to the in-core first end 10a than the center in the axial direction. Specifically, the wing portion 14 is arranged at the in-core first end 10a. The wing portion 14 extends outward in the radial direction from the in-core first end 10a of the in-core 10 and is formed in an annular shape. The wing portion 14 extends over the entire circumference in the circumferential direction. The outer diameter (maximum outer diameter) of the wing portion 14 is larger than the inner diameter (minimum inner diameter) of the joint body 101. In the first embodiment, the outer diameter of the wing portion 14 is larger than the inner diameter (minimum inner diameter) of the joint body 101 over the entire length of the wing portion 14 in the axial direction. The in-core cylindrical portion 12 is formed to have a constant outer diameter in the axial direction. Note that the in-core 10 will be explained in detail later.

The in-core 10 is taken out from the joint body 101 and inserted into the end of the pipe P. At this time, the in-core 10 is placed in the pipe P with the wing portions 14 of the in-core 10 abutted against the end surface of the pipe P. Moreover, at this time, the in-core 10 suppresses the deformation of the pipe P inward in the radial direction. Therefore, when the pipe P is inserted into the pipe joint 100, the retaining rings 104a and 104b firmly bite into the pipe P. The in-core 10 is formed by injection molding of a material having higher rigidity than the material forming the pipe P, such as a synthetic resin material.
As the synthetic resin material, for example, super engineering plastics (thermoplastic resins) such as polyphenylene sulfide resin (PPS), polyphenylsulfone resin (PPSU), polyethersulfone resin (PES), and polysulfone resin (PSU) are used. It can be selected arbitrarily based on quality design.
Note that a glass fiber-reinforced resin obtained by reinforcing the super engineering plastic with glass fibers may be arbitrarily selected based on quality design depending on the application.

The pipe P is formed, for example, by extrusion molding of a synthetic resin material.
Examples of the synthetic resin materials include crosslinked polyethylene, polybutene, vinyl chloride (PVC), polysulfone resin (PSU), polycarbonate resin (PC), polyamide resin (PA), polyacetal resin (POM), and polyphenylsulfone resin (PPSU). ), polyphenylene sulfide resin (PPS), glass fiber reinforced PPS, polyvinylidene fluoride (PVDF), etc., can be arbitrarily selected based on quality design according to the purpose. The pipe P is preferably made of crosslinked polyethylene.

Note that by housing the in-core 10 in the joint body 101, space can be saved and loss of the in-core 10 can be prevented. Therefore, for example, when packing the pipe fitting 100, it is preferable to store the in-core 10 in the fitting body 101.
The pipe joint 100 has a symmetrical shape on both sides in the axial direction with respect to the center in the axial direction. A pipe P is inserted into the pipe joint 100 from both sides in the axial direction. Pipe joint 100 connects two pipes P.

Next, a method of connecting the pipe P using the pipe joint 100 will be explained. This connection method is a method of connecting two pipes P using a pipe joint 100. In this connection method, the two pipes P are inserted into mutually different ends of the pipe fitting 100 to connect the pipe fitting 100 and the pipes P.
The outer diameter of the pipe P is equal to or less than the outer diameter of the wing portion 14 of the in-core 10 .

When connecting the pipe fitting 100 and the pipe P, first, the in-core 10 is extracted from the fitting body 101 as described above. Thereafter, the in-core 10 is inserted into the pipe P, and the wing portions 14 of the in-core 10 are butted against the end surface of the pipe P. At this time, the wing portion 14 of the in-core 10 abuts against the end face (edge) of the pipe P, and further entry of the in-core 10 into the pipe P is restricted. As a result, the wing portion 14 of the in-core 10 is exposed from the pipe P to the outside. In other words, when the in-core 10 is inserted into the pipe P, the wing portion 14 of the in-core 10 and the end surface of the pipe P are lined up in this order from the outside of the pipe P along the axial direction.

Thereafter, the pipe P into which the in-core 10 has been inserted is inserted into the joint body 101 with the wing portion 14 of the in-core 10 leading the pipe P. At this time, the wing portion 14 of the in-core 10 sequentially overcomes the retaining ring 104b, the spacer 104c, and the retaining ring 104a in the axial direction. Then, the retaining ring 104a abuts against the base 103b, and the retaining ring 104b abuts against the spacer 104c.

In the pipe joint 100 and the pipe P connected as described above, the packing 103a is in close contact (pressure contact) with the outer peripheral surface of the pipe P. In this state, the pipe P is arranged within the joint body 101.

As described above, in the pipe fitting 100 of the first embodiment, the watertight portion 103 is composed of a gasket 103a that abuts against the locking step at the back of the fitting body 101, and a base 103b, and water is sealed on the outer surface of the pipe P (external surface watertightness) by obtaining surface pressure from the compressive force generated when the pipe P is inserted and the compressive force generated by the pipe P expanding when internal pressure is applied inside the pipe (self-watertightness).
When the in-core 10 is inserted into the pipe P, the in-core 10 suppresses deformation of the pipe P.

<Incore>
Incore 10 will be explained in detail below. Note that the center axis of the in-core 10 is arranged coaxially with the center axis of the pipe joint 100. Therefore, the axial direction along the central axis of the in-core 10 is the same as the axial direction of the pipe fitting 100.

As shown in FIG. 3, the inner circumferential surface 15 of the in-core 10 is penetrated in the axial direction from the in-core first end 10a to the in-core second end 10b, and the opening formed by the inner circumferential surface 15 becomes a flow path. Hereinafter, the inner diameter (opening diameter) of the inner circumferential surface 15 may be referred to as the flow path diameter. Further, one end portion of the inner circumferential surface 15 is the same as the in-core first end 10a of the in-core 10. The other end of the inner peripheral surface 15 is the same as the in-core second end 10b of the in-core 10. The inner circumferential surface 15 has a first inner circumferential surface 16 , a second inner circumferential surface 17 , and an intermediate position 18 . The intermediate position 18 is a location where the first inner circumferential surface 16 and the second inner circumferential surface 17 are butted against each other.

The first inner circumferential surface 16 is a portion from the in-core first end 10a to the intermediate position 18 in the axial direction. The first inner circumferential surface 16 is formed, for example, into a tapered surface (slanted surface) with a taper angle (inclination angle) θ1 so that the flow path diameter decreases from the in-core first end 10a toward the intermediate position 18. The second inner circumferential surface 17 is a portion from the in-core second end 10b to the intermediate position 18 in the axial direction. The second inner circumferential surface 17 is formed, for example, into a tapered surface (slanted surface) with a taper angle (inclination angle) θ2 such that the diameter decreases from the in-core second end 10b toward the intermediate position 18.
The taper angle θ1 and the taper angle θ2 are determined so that the minimum diameter (minimum flow path diameter) of the first inner peripheral surface 16 and the minimum diameter (minimum flow path diameter) of the second inner peripheral surface 17 are the same at the intermediate position 18. It will be done. It is desirable that the taper angle θ1 and the taper angle θ2 be selected from a range of, for example, greater than 0° and less than or equal to 3°.
The reason why it is desirable to select the taper angle θ1 and the taper angle θ2 from a range of greater than 0° and less than or equal to 3° will be explained in detail later.

The intermediate position 18 is located midway between the in-core first end 10a and the in-core second end 10b in the axial direction. The intermediate position 18 is a location where the end portion where the first inner circumferential surface 16 has the smallest diameter and the end portion where the second inner circumferential surface 17 has the smallest diameter are butted against each other. That is, the intermediate position 18 is a portion where the flow path diameter is the minimum diameter on the inner circumferential surface 15. In other words, the in-core 10 is formed such that the inner circumferential surface 15 has the minimum flow path diameter at the intermediate position 18.

As shown in FIG. 3, the minimum diameter is located on the one end (incore first end) 10a side having a protrusion (wing portion) 14 on the outer peripheral surface from the middle of the incore 10 in the axial direction of the incore 10. That is, the minimum diameter is located between the middle of the incore 10 and the one end 10a in the axial direction of the incore 10. The minimum diameter may be located on the other end (incore second end) 10b side from the middle of the incore 10 in the axial direction of the incore 10. For example, when the incore first end 10a abuts against the step 113, the minimum diameter is located on the incore first end 10a side in the axial direction than the packing 103a. This makes it easier for the resin to flow from the thick wall to the thin wall during molding.

The plurality of gate marks are on the inner circumferential surface 15 of the in-core 10 or on the end surface 21 of the one end portion 10a. In this embodiment, as shown in FIG. 3, two gate marks 20 are located on the end surface 21 of the end portion 10a. When a plurality of gate marks 20 are present on the end surface 21 of one end portion 10a, a pin gate is preferable. By using a pin gate, the gate marks after molding can be made smaller, making the remaining gate less noticeable. Further, in order to mold the end portion of the in-core 10 as designed, it is necessary to apply a certain amount of holding pressure, but by employing a pin gate, it becomes easier to apply holding pressure. Further, even when a seal is attached to the end face 21 of the in-core 10 at the time of shipping the joint, the seal can be suitably attached by reducing the gate mark.
When a plurality of gate marks are present on the inner circumferential surface 15 of the in-core 10, the plurality of gate marks are located closer to the one end portion 10a than the middle of the in-core 10 in the axial direction of the in-core 10. That is, the plurality of gate marks are located between the middle of the in-core 10 and one end portion 10a in the axial direction of the in-core 10. When a plurality of gate marks are present on the inner peripheral surface 15, a submarine gate (tunnel gate) is preferable. By using a submarine gate, there is little gate residue after molding, and the small gate diameter makes it easy to remove the runner.
When a plurality of gate marks are present on the inner circumferential surface 15 of the in-core 10, the plurality of gate marks extend from the end face (end face of one end portion 10a) 21 of the in-core 10 to 1/1 of the total length L3 of the in-core 10 in the axial direction of the in-core 10. Preferably, it is between 2 and 2. That is, as shown in FIG. 3, the plurality of gate marks are located in the gate mark range GA1 of the inner circumferential surface 15 of the in-core 10 in the axial direction of the in-core 10. The gate trace range GA1 is a range from the end surface (the end surface of one end portion 10a) 21 of the in-core 10 to 1/2 of the total length L3 of the in-core 10. In this case, even if the holding pressure is not high, the moldability of the end portion of the in-core 10 can be improved.

<Mold structure>
As shown in FIGS. 3 and 4, the in-core 10 is molded by injection molding using a mold structure 50, for example. The mold structure 50 includes a mold 51 and a core pin 52. The mold 51 and the core pin 52 can be arbitrarily selected from general steel materials based on quality design according to the application.
The mold 51 molds the outer peripheral part 19 of the in-core 10 (specifically, the outer peripheral part of the in-core cylindrical part 12 and the wing part 14). The mold 51 includes, for example, a first mold 55 and a second mold 56. The first mold 55 and the second mold 56 are configured to be able to open and close. The first mold 55 has a first mold molding surface 55a. The second mold 56 has a second mold molding surface 56a. The first molding surface 55a and the second molding surface 56a are molding surfaces for molding the outer peripheral portion 19 of the in-core 10.

The core pin 52 is formed by, for example, electric discharge machining, lathe machining, or the like. The core pin 52 shapes the inner circumferential surface 15 of the in-core 10. The core pin 52 consists of a first core pin 57 and a second core pin 58 that are divided in the axial direction. The first core pin 57 and the second core pin 58 are configured to be able to open and close the mold in the axial direction.

The first core pin 57 has a first dividing surface (dividing surface) 61 that forms the first inner circumferential surface 16 of the in-core 10 . That is, the first dividing surface 61 is formed to correspond to the first inner circumferential surface 16 in the range from the distal end 57a to the proximal end 57b. The base end portion 57b is a portion corresponding to the in-core first end 10a. The first dividing surface 61 is inclined from the first inner circumferential surface 16 so that the pin diameter increases with respect to the drawing direction indicated by arrow A (ie, the mold opening direction). Specifically, it is desirable that the first dividing surface 61 be formed with a taper angle (angle of inclination) θ3 greater than 0° and less than 3°, for example. The taper angle θ3 of the first dividing surface 61 is the same as the taper angle θ1 of the first inner circumferential surface 16.
The first core pin 57 has a tip end 57a with a minimum pin diameter, and a base end 57b with a maximum pin diameter. Hereinafter, the pin diameter of the tip portion 57a may be referred to as a first tip pin diameter. The pin diameter of the base end portion 57b is sometimes referred to as a first base end pin diameter.

Here, the core pin 52 is divided into two parts, a first core pin 57 and a second core pin 58. Therefore, in the first core pin 57, the pin length L1 of the first dividing surface 61 (the length of the first core pin) is kept short in the axial direction. Hereinafter, the pin length L1 of the first dividing surface 61 may be referred to as "the pin length L1 of the first core pin 57." The first core pin 57 is desirably formed so that the pin length L1 is, for example, 0.1 to 0.9 times the total length L3 of the in-core 10.

The second core pin 58 has a second dividing surface (dividing surface) 62 that forms the second inner circumferential surface 17 of the in-core 10 . That is, the second dividing surface 62 is formed to correspond to the second inner circumferential surface 17 in the range from the distal end 58a to the proximal end 58b. The base end portion 58b is a portion corresponding to the in-core second end 10b. The second dividing surface 62 is inclined from the second inner circumferential surface 17 so that the pin diameter increases with respect to the drawing direction indicated by arrow B (ie, the mold opening direction). It is desirable that the second dividing surface 62 be formed with a taper angle (angle of inclination) θ4 greater than 0° and less than 3°, for example. The taper angle θ4 of the second dividing surface 62 is the same as the taper angle θ2 of the second inner circumferential surface 17.
The second core pin 58 has a tip end 58a with a minimum pin diameter, and a base end 58b with a maximum pin diameter. Hereinafter, the pin diameter of the tip portion 58a may be referred to as a second tip pin diameter. The pin diameter of the base end portion 58b is sometimes referred to as a second base end pin diameter. Note that the taper angle θ3 of the first dividing surface 61 and the taper angle θ4 of the second dividing surface 62 are determined so that the first tip pin diameter and the second tip pin diameter are the same.

Here, the core pin 52 is divided into two parts, a first core pin 57 and a second core pin 58. Therefore, in the second core pin 58, the pin length L2 of the second dividing surface 62 (length of the second core pin) is kept short in the axial direction. Hereinafter, the pin length L2 of the second dividing surface 62 may be referred to as "the pin length L2 of the second core pin 58." It is desirable that the second core pin 58 be formed such that the pin length L2 is within a range of 0.1 to 0.9 times the total length L3 of the in-core 10, for example.

The mold structure 50 has multiple gates (not shown). The plurality of gates are located between 1/2 of the total length L3 of the in-core 10 from a position corresponding to the end surface (the end surface of the in-core first end 10a) 21 of the in-core 10 in the axial direction of the in-core 10. That is, as shown in FIG. 4, the plurality of gates are located in the gate range GA2 in the axial direction of the in-core 10. The gate range GA2 is a range of 1/2 of the total length L3 of the in-core 10 from a position corresponding to the end surface (the end surface of one end portion 10a) 21 of the in-core 10. The gate mark range GA1 of the in-core 10 is the same range as the gate range GA2 of the mold structure 50 corresponding to the in-core 10.
The gate (not shown) is formed in the cavity 67 at a position corresponding to the inner circumferential surface 15 of the in-core 10 so as to be able to communicate with it, for example, when the mold structure 50 is in a clamped state. Further, the gate is formed so as to be able to communicate with a runner (not shown) when the mold structure 50 is in a clamped state. The gate is formed so that the runner can communicate with the cavity 67 when the mold structure 50 is in a clamped state.
The cavity 67 is formed by the first molding surface 55a, the second molding surface 56a, the first dividing surface 61, the second dividing surface 62, etc. when the mold structure 50 is clamped.
Note that, for example, the gate may be formed in the first mold 55. In this case, for example, when the mold structure 50 is in a clamped state, the gate is formed in the cavity 67 at a position corresponding to the wing portion 14 of the in-core 10 so as to be able to communicate therewith. Further, the gate method can be arbitrarily selected based on the design of side gates, pin gates, etc. depending on the application.

The reason why it is desirable to select the taper angle θ3 and the taper angle θ4 from a range of greater than 0° and less than or equal to 3° will be explained in detail later. Further, the reason why it is desirable to select the pin length L1 and the pin length L2 from the range of 0.1 to 0.9 times the total length L3 of the in-core 10 will be explained in detail later.

<Incore manufacturing method>
Next, a method for manufacturing the incore 10 by injection molding using the mold structure 50 will be described with reference to Fig. 3 and Fig. 4. In the first embodiment, as an example, the incore 10 is formed by injection molding of a resin material, but it is also possible to similarly perform injection molding using other materials such as a metal material.

As shown in FIGS. 3 and 4, first, in the mold clamping process, the first mold 55, second mold 56, first core pin 57, and second core pin 58 of the mold structure 50 are clamped. . By clamping the mold structure 50, the distal end 57a of the first core pin 57 and the distal end 58a of the second core pin 58 are arranged in a butted state in the axial direction.
In this state, a cavity 67 is formed inside the mold structure 50 by the first molding surface 55a, the second molding surface 56a, the first dividing surface 61, and the second dividing surface 62. Further, the cavity 67 is communicated with the runner via a gate.

Next, in the injection step, molten resin is injected from the runner into the cavity 67 through the gate. By solidifying the molten resin injected into the cavity 67, the in-core 10 is molded by the first molding surface 55a, the second molding surface 56a, the first dividing surface 61, the second dividing surface 62, and the like. In particular, the first inner circumferential surface 16 is formed by the first dividing surface 61 . The second inner circumferential surface 17 is formed by the second dividing surface 62 .

Next, in the mold opening step, after the in-core 10 is molded in the cavity 67, the first mold 55, the second mold 56, the first core pin 57, and the second core pin 58 of the mold structure 50 are opened. do. Here, when opening the mold structure 50, in the step of pulling out the first core pin 57 and the second core pin, for example, after pulling out the first core pin 57 from the first inner circumferential surface 16 first, The second core pin 58 is pulled out from the second inner peripheral surface 17 in the opposite direction. The reason why the first core pin 57 is first pulled out from the first inner peripheral surface 16 and then the second core pin 58 is pulled out from the second inner peripheral surface 17 in the opposite direction will be explained in detail later.
By opening the mold structure 50, the in-core 10 is released from the first mold 55, the second mold 56, the first core pin 57, and the second core pin 58. This completes the step of forming the in-core 10 by injection molding using the mold structure 50.

According to the mold structure 50, the in-core manufacturing method, the in-core 10, and the pipe joint 100 described above, as shown in FIGS. 3 and 4, the core pin 52 has a first core pin 57 and a second core pin 58. By dividing the first core pin 57 into two, the length L1 of the first core pin 57 is kept short. The length L2 of the second core pin 58 is kept short. Thereby, when the first core pin 57 is pulled out from the first inner peripheral surface 16 and the second core pin 58 is pulled out from the second inner peripheral surface 17 in the opposite direction, deformation of the in-core 10 can be suppressed.

Further, by inclining the first dividing surface 61 of the first core pin 57, a draft angle can be formed in the first dividing surface 61 with respect to the first inner circumferential surface 16. By inclining the second dividing surface 62 of the second core pin 58, a draft angle can be formed in the second dividing surface 62 with respect to the second inner circumferential surface 17. Thereby, when the first core pin is extracted from the first inner circumferential surface 16 and the second core pin is extracted from the second inner circumferential surface 17, deformation of the in-core 10 can be better suppressed.

Here, if the core pin is integrally formed without being divided, the core pin becomes relatively long. Therefore, if a draft angle is formed on the dividing surface of the integral core pin, the pin diameter at the distal end of the core pin becomes too small and the pin diameter at the proximal end becomes too large. That is, in the in-core, it is conceivable that the thick portion corresponding to the tip of the core pin becomes too thick and the thin portion corresponding to the proximal end of the core pin becomes too thin.
Therefore, in the thick portion, the inner diameter of the inner circumferential surface becomes smaller, and the flow path diameter of the inner circumferential surface becomes smaller. As the flow path diameter of the inner circumferential surface becomes smaller, there is a concern that pressure loss due to a decrease in flow rate will occur when a large number of pipe joints are used, for example, in repair work for piping in an apartment building. Furthermore, it is possible that the moldability of the thin-walled portion deteriorates, resulting in short shots, and it is difficult to maintain the shape of the thin-walled portion.

Therefore, the core pin 52 is divided into a first core pin 57 and a second core pin 58, and the lengths of the first core pin 57 and the second core pin 58 in the axial direction are kept short. Therefore, in the first core pin 57, the pin diameter difference between the first tip pin diameter and the first proximal pin diameter can be kept relatively small. That is, in the first core pin 57, the diameter of the first tip end pin can be ensured to be large, and the diameter of the first proximal end pin can be kept small. Similarly, in the second core pin, the difference in pin diameter between the second tip end pin diameter and the second base end pin diameter can be kept relatively small. That is, in the second core pin 58, the diameter of the second tip end pin can be ensured to be large, and the diameter of the second base end pin can be kept small.

Therefore, in the in-core 10, it is possible to ensure a large inner diameter of the thick portion corresponding to the portion where the tip portion 57a of the first core pin 57 and the tip portion 58a of the second core pin 58 are butted against each other. The thick portion corresponds to the intermediate position 18 of the inner circumferential surface 15. The inner diameter of the intermediate position 18 is a portion of the inner circumferential surface 15 of the in-core 10 that is the smallest diameter. Thereby, by ensuring a large inner diameter of the thick portion (that is, the intermediate position 18), it is possible to ensure a large flow path diameter of the in-core 10.
In other words, in order to realize the maximum flow path diameter of the in-core 10, the core pin 52 is divided into two. Thereby, the minimum diameter of the in-core 10 was formed between the first core pin 57 and the second core pin 58.

In addition, in the in-core 10, the inner diameter of the thin portion corresponding to the base end portion 57b of the first core pin 57 can be kept small. This thin portion corresponds to the in-core first end 10a of the in-core 10. The in-core first end 10a is a portion of the first inner circumferential surface 16 that has the largest inner diameter.
Further, in the in-core 10, the inner diameter of the thin portion corresponding to the base end portion 58b of the second core pin 58 can be kept small. This thin portion corresponds to the in-core second end 10b of the in-core 10. The in-core second end 10b is a portion of the second inner circumferential surface 17 that has the largest inner diameter.
Therefore, by keeping the inner diameters of the in-core first end 10a and the in-core second end 10b small, the wall thicknesses of the in-core first end 10a and in-core second end 10b can be ensured to be suitable thicknesses. Thereby, the moldability of the in-core first end 10a and the in-core second end 10b can be improved, and the moldability of the in-core 10 can be ensured.

Further, it is desirable that the first dividing surface 61 of the first core pin 57 is formed so that the taper angle θ3 is greater than 0° and less than or equal to 3°. It is desirable that the second dividing surface 62 of the second core pin 58 be formed so that the taper angle θ4 is greater than 0° and less than 3°. The reason why the taper angle θ3 of the first dividing surface 61 and the taper angle θ4 of the second dividing surface 62 are set to a range of greater than 0° and equal to or less than 3° will be explained based on Table 1.

As shown in Table 1, when the taper angle θ3 of the first dividing surface 61 is 0°, when the first core pin 57 is extracted from the first inner circumferential surface 16 of the in-core 10, the first inner circumferential surface 16 is The first dividing surface 61 makes it difficult to mold smoothly. Similarly, when the taper angle θ4 of the second divided surface 62 is set to 0°, when the second core pin 58 is extracted from the second inner peripheral surface 17 of the in-core 10, the second inner peripheral surface 17 is 62, it is difficult to mold it smoothly. For this reason, it is conceivable that the first inner circumferential surface 16 and the second inner circumferential surface 17 become defective in molding.

Moreover, when the taper angle θ3 of the first dividing surface 61 is made larger than 3 degrees, the first inner circumferential surface 16 of the in-core 10 can be formed smoothly by the first dividing surface 61. Similarly, when the taper angle θ4 of the second dividing surface 62 is made larger than 3 degrees, the second inner circumferential surface 17 of the in-core 10 can be formed smoothly by the second dividing surface 62. However, when the taper angle θ3 and the taper angle θ4 are made larger than 3°, the flow path diameter becomes too small at the intermediate position 18 of the inner circumferential surface 15.
Furthermore, when the taper angle θ3 and the taper angle θ4 are made larger than 3°, in the in-core 10, the flow path diameters of the in-core first end 10a and the in-core second end 10b become too large. Therefore, it is conceivable that the wall thicknesses of the in-core first end 10a and the in-core second end 10b become too thin. For this reason, it is difficult to ensure the moldability of the in-core first end 10a and the in-core second end 10b.

Therefore, the taper angle θ3 of the first dividing surface 61 and the taper angle θ4 of the second dividing surface 62 were set to a range of greater than 0° and equal to or less than 3°. By ensuring that the first taper angle θ3 and the second taper angle θ4 are larger than 0°, the draft angle of the first core pin 57 and the second core pin can be suitably ensured. Therefore, when extracting the first core pin 57 from the first inner circumferential surface 16 of the in-core 10, the first inner circumferential surface 16 can be formed smoothly by the first dividing surface 61. Similarly, when extracting the second core pin 58 from the second inner circumferential surface 17 of the in-core 10, the second inner circumferential surface 17 can be formed smoothly by the second dividing surface 62. Thereby, deformation of the in-core 10 can be effectively suppressed.

Further, by suppressing the first taper angle θ3 and the second taper angle θ4 to 3° or less, a large flow path diameter at the intermediate position 18 in the in-core 10 can be ensured. Furthermore, by suppressing the first taper angle θ3 and the second taper angle θ4 to 3° or less, the thickness of the in-core first end 10a and the in-core second end 10b of the in-core 10 can be suitably ensured. Thereby, the moldability of the in-core first end 10a and the in-core second end 10b can be improved, and the moldability of the in-core 10 can be ensured.
Therefore, it is desirable to set the taper angle θ3 of the first dividing surface 61 and the taper angle θ4 of the second dividing surface 62 to a range of greater than 0° and equal to or less than 3°. Furthermore, it is particularly desirable to set the taper angle θ3 of the first dividing surface 61 and the taper angle θ4 of the second dividing surface 62 to a range of 0.5° or more and 3° or less.

Furthermore, it is desirable to form the first core pin 57 so that the pin length L1 is within a range of 0.1 to 0.9 times the total length L3 of the in-core 10. It is desirable to form the second core pin 58 so that the pin length L2 is within a range of 0.1 to 0.9 times the total length L3 of the in-core 10. The reason why the pin length L1 of the first core pin 57 and the pin length L2 of the second core pin 58 are set in the range of 0.1 to 0.9 times the total length L3 of the in-core 10 is explained based on Table 2. I will explain.

As shown in Table 2, for example, if the pin length L1 of the first core pin 57 is set to be 0 times or more and less than 0.1 times the total length L3 of the in-core 10, the pin length of the second core pin 58 The length L2 is greater than 0.9 times the total length L3 of the in-core 10. Here, the first dividing surface 61 of the first core pin 57 has a draft angle of taper angle θ3. The second dividing surface 62 of the second core pin 58 has a draft angle of taper angle θ4. Therefore, if the pin length L3 of the second core pin 58 is greater than 0.9 times the total length L3 of the in-core 10, the second tip pin diameter of the second core pin 58 becomes too small, and the flow path diameter It is difficult to secure a suitable size.
Note that even when the pin length L2 of the second core pin 58 is set to be 0 times or more and less than 0.1 times the total length L3 of the in-core 10, the first tip pin diameter of the first core pin 57 is small. This makes it difficult to ensure a suitable flow path diameter.

Further, for example, if the pin length L1 of the first core pin 57 is set to be greater than 0.9 times and less than 1 times the total length L3 of the in-core 10, the first tip pin diameter of the first core pin 57 becomes small. This makes it difficult to ensure a suitable flow path diameter.
Note that even when the pin length L2 of the second core pin 58 is set to be greater than 0.9 times and less than 1 time the total length L3 of the in-core 10, the second tip pin diameter of the second core pin 58 is small. This makes it difficult to ensure a suitable flow path diameter.

Therefore, the pin length L1 of the first core pin 57 and the pin length L2 of the second core pin 58 are set to be 0.1 to 0.9 times the total length L3 of the in-core 10. Therefore, the pin length L1 of the first core pin 57 and the pin length L2 of the second core pin 58 can be kept relatively short. Thereby, it becomes possible to realize the maximum flow path diameter on the inner circumferential surface 15 of the in-core 10. That is, it is possible to ensure a large flow path diameter at the intermediate position 18 on the inner circumferential surface 15.
Therefore, it is desirable to set the pin length L1 of the first core pin 57 and the pin length L2 of the second core pin 58 to 0.1 to 0.9 times the total length L3 of the in-core 10. Furthermore, it is particularly desirable to set the pin length L1 of the first core pin 57 and the pin length L2 of the second core pin 58 to a range of 0.3 to 0.7 times the total length L3 of the in-core 10. .

Further, according to the in-core manufacturing method, in the step of pulling out the first core pin 57 and the second core pin, the first core pin 57 is first pulled out from the first inner circumferential surface 16, and then the second core pin 58 is pulled out. It was designed to be pulled out from the second inner circumferential surface 17 in the opposite direction.
Therefore, when pulling out the first core pin 57, the in-core 10 can be supported by the second core pin 58. Thereby, the first core pin 57 can be extracted from the first inner circumferential surface 16 of the in-core 10 while the in-core 10 is stabilized. Therefore, deformation of the in-core 10 can be better suppressed.
Note that even if the second core pin 58 is first pulled out from the second inner peripheral surface 17 and then the first core pin 57 is pulled out in the opposite direction from the first inner peripheral surface 16, the in-core 10 is deformed. This can be suppressed even better.

The incore 10 is also formed by injection molding of a synthetic resin material using the mold structure 50. This allows the material and processing costs to be kept low compared to forming the incore 10 by pressing and drawing a metal material such as stainless steel.

Further, in the inner peripheral surface 15 of the in-core 10, the taper angle θ1 of the first inner peripheral surface 16 is the same as the taper angle θ3 of the first dividing surface 61. The taper angle θ2 of the second inner peripheral surface 17 is the same as the taper angle θ4 of the second dividing surface 62. Therefore, the taper angle θ1 of the first inner circumferential surface 16 and the taper angle θ2 of the second inner circumferential surface 17 can be determined in the same manner as the taper angle θ3 of the first dividing surface 61 and the taper angle θ4 of the second dividing surface 62. preferable.
That is, it is desirable to select the taper angle θ1 of the first inner circumferential surface 16 and the taper angle θ2 of the second inner circumferential surface 17 from a range of greater than 0° and less than or equal to 3°. Furthermore, it is particularly desirable to set the taper angle θ1 and the taper angle θ2 to a range of 0.5° or more and 3° or less.

Further, in the inner circumferential surface 15 of the in-core 10, an intermediate position 18 between the first in-core end 10a and the second in-core end 10b is formed to have the smallest diameter. Therefore, according to the in-core 10, by dividing the inner circumferential surface 15 into the first inner circumferential surface 16 and the second inner circumferential surface 17 at the intermediate position 18 in the axial direction, the first inner circumferential surface 16 can be connected to the first core pin. It can be formed by the first dividing surface 61 of 57. The second inner circumferential surface 17 can be formed by the second dividing surface 62 of the second core pin 58 .
Thereby, the pin length L1 of the first core pin 57 and the pin length L2 of the second core pin 58 can be kept short. Therefore, when the first core pin 57 is extracted from the first inner circumferential surface 16 of the in-core 10 and the second core pin 58 is extracted from the second inner circumferential surface 17 of the in-core 10, deformation of the in-core 10 can be suppressed. Can be done.

Here, the minimum diameter of the inner circumferential surface of the in-core is determined by, for example, the pin length and draft angle of the core pin. That is, when the draft angles of the core pins are the same, by shortening the pin length of the core pins, a larger minimum diameter can be ensured. Therefore, in the first embodiment, by forming the inner circumferential surface 15 of the in-core 10 with the first core pin 57 and the second core pin 58, it is possible to ensure a large minimum diameter at the intermediate position 18. Thereby, a large flow path diameter of the in-core 10 can be ensured.

Furthermore, when the draft angles of the core pins are the same, the maximum diameter of the core pin (specifically, the base end portion) can be kept small by shortening the pin length of the core pin. Therefore, in the first embodiment, the inner circumferential surface 15 of the in-core 10 is formed by the first core pin 57 and the second core pin 58, so that the pin length L1 of the first core pin 57 and the second core pin 58 pin length L2 was shortened.
Therefore, the maximum diameter at the first in-core end 10a and the second in-core end 10b of the in-core 10 can be kept small. The in-core first end 10a and the in-core first end 10a are parts that become thin parts. Therefore, by keeping the maximum diameters of the in-core first end 10a and the in-core second end 10b small, the wall thicknesses of the in-core first end 10a and the in-core first end 10a can be ensured to be suitable thicknesses. Thereby, the moldability of the in-core first end 10a and the in-core first end 10a can be improved, and the moldability of the in-core 10 can be ensured.

Note that the technical scope of the present invention is not limited to the embodiments described above, and various changes can be made without departing from the spirit of the present invention.

For example, the pipe fitting 100 is not limited to the configuration shown in the above embodiment.

In addition, it is possible to appropriately replace the components in this embodiment with well-known components without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10... In-core, 10a... In-core first end (one end part), 10b... In-core second end (other end part), 14... Wing part, 15... Inner circumferential surface, 16... First inner circumferential surface, 17... Second Inner peripheral surface, 18... intermediate position, 19... outer peripheral part, 20... gate mark, 21... end face, 50, 70... mold structure, 51... mold, 52... core pin, 57... first core pin, 58... th 2 core pin, 61...first dividing surface (dividing surface), 62...second dividing surface (dividing surface), 100...pipe joint (fitting), L1...pin length of the first core pin (first core pin length) L2... Pin length of the second core pin (length of the second core pin), L3... Total length of the in-core, θ3... Taper angle of the first dividing surface, θ4... Taper angle of the second dividing surface.

Claims (11)

A mold structure used for molding the inner core of a joint by injection molding,
A mold for molding the outer peripheral part of the cylinder of the in-core, and a core pin for molding the inner peripheral surface,
The core pin has a mold structure consisting of a first core pin and a second core pin that are divided in the axial direction of the joint. The mold structure according to claim 1, wherein a dividing surface between the first core pin and the second core pin is inclined so that the pin diameter increases with respect to the drawing direction. The mold structure according to claim 2, wherein the taper angle of the parting surface between the first core pin and the second core pin is greater than 0° and less than or equal to 3°. The mold structure according to claim 2, wherein the lengths of the first core pin and the second core pin are 0.1 to 0.9 times the total length of the in-core. A method for manufacturing an in-core using the mold structure according to any one of claims 1 to 4, wherein the first core pin is first pulled out, and then the second core pin is pulled out in the opposite direction. A method for manufacturing in-core, comprising a process. An in-core, whose inner circumferential surface is formed to have a minimum diameter at the midpoint between one end and the other end. The in-core according to claim 6, wherein the minimum diameter is located at a position closer to the one end portion having a protrusion on the outer peripheral surface than the middle of the in-core in the axial direction. The in-core according to claim 6, wherein the plurality of gate marks are on the inner circumferential surface, and are located at positions closer to the one end portion having the protrusion on the outer circumferential surface than the middle of the in-core in the axial direction. The in-core according to claim 6, wherein a plurality of gate marks are located on the end surface of the one end portion having a protrusion on the outer peripheral surface. The joint body,
an in-core disposed on the inner peripheral surface of the joint body;
Equipped with
The inner circumferential surface of the in-core is formed to have a minimum diameter at an intermediate position between one end and the other end.
pipe fittings. The pipe joint according to claim 10, wherein the minimum diameter is located at a position closer to the one end portion having a protrusion on the outer peripheral surface than the middle of the inner core in the axial direction.

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